Electrical contact test tool



Feb. 4, 1969 R. B. HEN'DRY 3,425,271

ELECTRICAL CONTACT TEST TOOL Filed Aug. 15, 1966 L9 :9 s .32 I6 r fimjuka i INVENTOR. ROBERT B. HENDRY BY Q/LM ATTORNEYS I United States Patent 2 Claims ABSTRACT OF THE DISCLOSURE The device disclosed is for checking the proper seating of electrical contact pins within a connector plug and comprises, a body having a chamber therein, a rod disposed in said body and mounted for axial movement therein, spring means in said chamber normally positioning said rod in one position of axial adjustment, said rod having an end portion disposed exteriorly of said body and having means thereon for engaging an electrical contact, and indicator means on said end portion for visually indicating the amount of rod movement when the tool is pressed against a contact being tested.

.This invention generally relates to testing equipment for electrical contacts, and is more particularly directed towards a simple mechanical device to check on the proper insertion of contact elements in an electrical connector.

Many electrical assemblies utilize electrical connectors having a plurality of male and/or female contacts extending therefrom. Improper contact insertion results in an inoperative assembly, and excessively high rejection rates have been experienced as a result. Visual inspection will not indicate whether the contacts are properly seated or whether they will move back upon the application of some predetermined pressure or force.

It is accordingly an object of the present invention to provide a test tool which is extremely simple in construction and operation, and which may be used to readily ascertain whether or not a contact has been properly installed in an electrical connector.

Another object of this invention is to provide a tool of the character described which may be used on both male and female contacts at the time of assembly of the latter so that upon determination of an improperly seated contact, the same may be easily reinserted and again checked.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred form of the invention which is illustrated in the drawing accompanying and forming part of the specification. It is to be understood, however, that variations in the showing made by the said drawing and description may be adopted within the scope of the invention as set forth in the claims.

Referring to said drawing:

FIGURE 1 is a perspective view of the tool of the present invention testing a contact.

FIGURE 2 is a longitudinal cross-sectional view of the tool.

FIGURE 3 represents a pair of adaptors for use with the tool, the left hand adaptor being used for checking female contacts and the right hand adaptor being used for checking male contacts.

As above mentioned, the tool of this invention is used to check the proper seating of contacts within an electrical connector, such as the male contacts 6 forming part of a connector assembly 7 as illustrated in FIGURE 1. By way of example, if a contact is improperly seated, a pressure of from about two to six pounds will move the conice tact rearwardly, i.e., towards the assembly 7. Thus, by having a properly calibrated tool, the amount of force applied to the contacts may be easily determined, and adequate seating may be readily insured.

The instant tool, designated by the numeral 8 in the drawing, includes a cylindrical 'boly 9 adapted to be held in the hand of the tester. Each end of the body is provided with a plug or closure 12 having aligned bores 13 in communication and aligned with the longitudinal axis of the body chamber 14. They inner ends of the closures have opposed transaxial surfaces 16 defining the ends of the chamber 14.

Extending through the chamber 14 and bores 13 is a rod 18. The central portion 19 of the rod has a diameter no greater than and preferably less than that of the bores 13. Outwardly extending portions 21 of the rod are of substantially the same diameter as the bores and are slidably engaged in the latter. As particularly noted in FIGURE 2 of the drawing, the portions 21 each terminates in a shoulder 22 axially spaced from the outer end surface 23 of closures 12 for a purpose presently to be explained. Each rod end includes a diametrically reduced portion 24 extending from portion 21, an enlarged collar 26 and a threaded shank 27.

A spring 29 is disposed in chamber 14 and encompasses the central rod portion 19. Washers 31 are positioned against the surfaces 16 and resiliently maintained in such position by the spring. The washer apertures are sufficient for free sliding movement of rod portion 19, but are smaller than the diameter of rod portions 21, a shoulder 32 being defined at the juncture of such portions normally coplanar with surface 16. Consequently upon any axial movement of the rod, one or the other of the rod shoulders 32 will engage its Washer 31 and urge the same inwardly of chamber 14 against the spring force. Obviously with the arrangement shown, the rod will normally be maintained in the centered position shown in the drawing.

Since the spring has a predetermined compression factor, if an end of rod 18 is placed against a contact 6, and the tool pressed towards such contact, the degree of axial displacement of the rod is directly related to the pressure or force applied to the contact. The exposed rod portions can be supplied with suitable indicia to indicate degree of rod movement, but as here shown, shoulder 22 may constitute one gage line, and a shoulder 34 defined at the juncture of rod portion 24 and collar 26 defining another. By way of example, for many contact assemblies, if the contact will resist a force of about two to six pounds, it indicates a proper seating. Thus, the strength of spring 29 is such that when shoulder 22 aligns with surface 23, a two pound force is indicated. Further rod movement and further spring compression until shoulder 34 aligns with such surface would indicate a six pound force. It will be clear that the tool as shown is completely bi-directional in use, i.e. either end of rod 18 may be applied to the contact being tested.

To facilitate engagement of the rod ends with the contacts, adaptors are provided. These adaptors may be of any desired size to accommodate the desired size of contacts, and as shown in FIGURE 3 preferably include adaptors for both male and female contacts. For the male contacts 6 shown in FIGURE 1, an adaptor 41 is provided. This adaptor has an internally threaded portion 42 adapted for engagement with rod shank 27. The adaptor body 43 has a recess 44 for receiving the contact 6. When the contacts are female, a male adaptor 46 is used. This adaptor likewise has an internally threaded portion 47 to permit attachment thereof to the rod shank. The body 48 merely consists of a short cylindrical shaft which may be releasably inserted in a female contact element.

By virtue of the interchangeability of the adaptors on 3 the rod 18 and the bidirectional character of the latter, one end of the tool may have a male adaptor and the other end a female adaptor. Similarly, different size adaptors may be releasably secured to the tool ends, all for the purpose of facilitating rapid testing of the contacts with a minimum of effort.

What is claimed is:

1. A testing tool for electrical contacts comprising a body having a chamber therein, a rod disposed in said body and mounted for axial movement therein, spring means in said chamber normally positioning said rod in one position of axial adjustment, said rod having an end portion disposed exteriorly of said body and having means thereon for engaging an electrical contact, and indicator means on said end portion for visually indicating the amount of rod movement when the tool is pressed against a contact being tested, said body provided with end closure means having axially aligned bores and internal opposed transaxial surfaces defining the ends of said body chamber, said rod having a central portion axially disposed in said chamber and diametrically enlarged portion positioned in said bores, said spring means extending between said surfaces, said enlarged portions of the rod operatively compressing said spring upon axial movement of the rod.

2. A tool as set forth in claim 1 in which a washer is provided around said central rod portion at each end of said spring with the aperture in such washers being smaller in diameter than the diameter of said enlarged rod portions whereby movement of the latter will urge a washer against the spring and compress the latter in said chamber.

References Cited UNITED STATES PATENTS 1,637,421 8/1927 Lipschutz.

1,961,368 6/1934 Larson 73-141 2,450,188 9/1948 De Graaf 73 141 2,522,544 9/1950 Seyboth 7381 XR 2,622,439 12/1952 Copper 73-80 2,816,439 12/1957 Hayes 73141XR 3,153,956 10/1964 Zdrakas 73 141 XR 3,292,430 12/1966 Collier et a1. 73 -141 RICHARD C. QUEISSER, Primary Examiner.

CHARLES A. RUEHL, Assistant Examiner. 

